1. Field of the Invention
The present invention relates to a signal line module, in which functionality has been added to a signal line, and to a communication terminal including such a signal line module.
2. Description of the Related Art
To date, communication terminal apparatuses such as cellular phones have become more compact and functional. Hence, due to restrictions in positions at which various electronic components are arranged in a communication terminal apparatus, a feeding circuit device such as an RFIC chip needs to be placed in a position spaced apart from a radiation element in some cases. An example configuration in such a case is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2006-325093.
FIG. 14 is a schematic configuration diagram of a communication terminal apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2006-325093. Here, a substrate 2 including a substrate ground formed thereon, an antenna 5, and a wireless circuit 3 are housed in a casing 1. The wireless circuit 3 is connected to the antenna 5 through a feed line 4 and an antenna matching circuit 8.
However, in general, connectors need to be used when a coaxial cable (the feed line 4 in the example of FIG. 14) is connected to an RFIC (the wireless circuit 3) and the antenna matching circuit 8 and, hence, power transmission loss due to an impedance mismatch between the line and the connectors may be generated. Further, since a matching circuit needs to be arranged in the vicinity of a radiation element (the antenna 5), a separate substrate for the matching circuit needs to be arranged in the vicinity of the radiation element. Hence, the antenna characteristics of the radiation element may be degraded due to the influence of a ground conductor formed on this separate substrate.